Be Certain of The origin
Brother of The Benz.
A oil leak from any area/item above the oilpan flange presents itself as a pan leak.
I'm positive you have checked other areas as well.
My W124030 at 165,000 miles developed a small leak that appeared to be from the oil pan.
Cleaning the tranny's sides and pan area helped to isolate the possible leak area.
On the drivers side of the transmission case is a large plug with a 17mm allen socket(double check the size).
This is the band strut retaining plug and on it's pass through of the housing has 2 "O" ring seals.
After years these seal become hard and leak.
There may be a technique to replace tese without removing the tranny?
In my case I backed the plug out approx 2 turns and sprayed it with brake cleaner for cleansing.
Using electrical solder(0.015"dia), I wrapped a turn around the plug(clockwise) over lapping the ends and applied RTV and tightened to compress the solder.
I've been told by one of our Moderators that damage can occur repairing this leak this way.
It has been 9,000 miles and the leak is stopped and, cross my fingers no damage.
Happy Trails beep Beep from the Spiderman in Houston!!!